At first sight, one could think this picture is a scale model of some narrow moutains, like Bryce Canyon… Actually it represents crimes in East London, an cardboard artwork by the Londoner artist Abigail Reynolds, called Mount Fear. Here is what can be read on the artist’s webpage:
The terrain of Mount Fear is generated by data sets relating to the frequency and position of urban crimes. Precise statistics are provided by the police. Each individual incident adds to the height of the model, forming a mountainous terrain.
All Mount Fear models are built on the same principals. The imaginative fantasy space seemingly proposed by the scupture is subverted by the hard facts and logic of the criteria that shape it. The object does not describe an ideal other-worldly space separated from lived reality, but conversely describes in relentless detail the actuality of life on the city streets.
No mention of the statistical method used (kernel, Dirichlet process density estimation?). Some crime data can be found on UNdata for example, or here for an interactive map. It reminds a great work by David Kahle about crime in Houston, combining ggplot2 and GoogleMap. He won a ggplot2 case study competition for this. His code is available here. I like in particular the contour plot, with cool rainbow colors, where both the crime level and the map background are clearly visible.